The Duchess of Cambridge, 34 — who is already a mom to Prince George, 2, and Princess Charlotte, 1 — stepped out with what looked like a tiny baby bump at a royal event in London on Wednesday, May 4.

Kate, William, George and Charlotte in December 2015.

Earlier this month, sources exclusively revealed to Life & Style that Kate and her husband, Prince William, 33, are expecting twins! "Kate and William were totally shocked when they found out," an insider told the magazine."They couldn't speak at first and both burst out laughing and crying."